Packaging and storage—
Preserve in tight, light-resistant containers.
Labeling—
The labeling indicates the Dissolution Test with which the product complies.
Identification—
Examine the chromatograms obtained in the test for Related compounds: the principal spot obtained from the test solution is similar in RF value, and color to that obtained from the Standard solution.
Dissolution 
711
—
Test 1:
If the product complies with this test, the labeling indicates that it meets USP Dissolution Test 1.
Medium:
0.1 N hydrochloric acid; 500 mL.
Apparatus 1:
120 rpm.
Time:
60 minutes.
Procedure—
Determine the amount in solution in portions of the solution under test that previously have been passed through a glass-fiber filter from fluorometric measurements at an excitation wavelength of 315 nm and an emission wavelength of 445 nm, using
Dissolution Medium as the blank, in comparison with a Standard solution having a known concentration of
USP Bromocriptine Mesylate RS in the same
Medium. A volume of alcohol not to exceed 5% of the total volume of the Standard solution may be used to bring the standard into solution prior to dilution with 0.1 N hydrochloric acid.
Tolerances—
Not less than 80% (Q) of the labeled amount of bromocriptine (C32H40BrN5O5) is dissolved in 60 minutes.
Test 2:
If the product complies with this test, the labeling indicates that it meets USP Dissolution Test 2.
Medium:
0.1 N hydrochloric acid; 500 mL.
Apparatus 2:
50 rpm.
Time:
30 minutes.
Standard preparation—
Dissolve an accurately weighed quantity of
USP Bromocriptine Mesylate RS in methanol, and quantitatively dilute with
Dissolution Medium to obtain a solution having a known concentration similar to the expected concentration of the test solution.
Mobile phase—
Prepare a filtered and degassed mixture of acetonitrile and 0.01 M ammonium carbonate (65:35). Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Chromatography system
(see
Chromatography 621)—The liquid chromatograph is equipped with a 300-nm detector and a 3.9-mm × 30-cm column that contains packing L1. The flow rate is about 1.5 mL per minute. Chromatograph replicate injections of the
Standard preparation, and record the peak responses as directed for
Procedure: the relative standard deviation is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 100 µL) of the Standard preparation and the solution under test into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity of C32H40BrN5O5 dissolved by comparison of the peak responses obtained from the Standard preparation and the solution under test.
Tolerances—
Not less than 80% (Q) of the labeled amount of bromocriptine (C32H40BrN5O5) is dissolved in 30 minutes.
Uniformity of dosage units 905:
meet the requirements.
Procedure for content uniformity—
[Caution—Protect all solutions from light.]
Solvent solution—
Dissolve 1.0 g of tartaric acid in 500 mL of water, add 500 mL of methanol, and mix.
Standard solution—
Using an accurately weighed quantity of
USP Bromocriptine Mesylate RS, prepare a solution in the
Solvent solution having a known concentration of about 0.04 mg per mL.
Test solution—
Transfer 1 Tablet into a 25-mL volumetric flask. Add about 15 mL of Solvent solution, and shake by mechanical means for 30 minutes. Dilute with Solvent solution to volume, and mix. Filter and dilute 10.0 mL of the clear filtrate with Solvent solution to 50.0 mL.
Procedure—
Concomitantly determine the absorbances of the
Test solution and the
Standard solution in 1-cm cells at the wavelength of maximum absorbance at about 306 nm, with a suitable spectrophotometer, using
Solvent solution as the blank. Calculate the quantity, in mg, of bromocriptine (C
32H
40BrN
5O
5) in the Tablet taken by the formula:
(654.59 / 750.70)(TC / D)(AU / AS),
in which 654.59 and 750.70 are the molecular weights of bromocriptine and bromocriptine mesylate, respectively;
T is the labeled quantity, in mg, of bromocriptine in the Tablet;
C is the concentration, in µg per mL, of
USP Bromocriptine Mesylate RS in the
Standard solution; D is the concentration, in µg per mL, of bromocriptine in the solution from the Tablet, based upon the labeled quantity per Tablet and the extent of dilution; and
AU and
AS are the absorbances of the solution from the Tablet and the
Standard solution, respectively.
Related compounds—
[NOTE—Conduct this test without exposure to daylight and with minimum exposure to artificial light. Perform the test rapidly, preparing and applying the test solution last.
] Transfer a quantity of finely powdered Tablets, equivalent to 20 mg of bromocriptine, to a conical flask. Add 10.0 mL of methanol, and mix for 20 minutes. Centrifuge the suspension at 4000 rpm for 10 minutes. The clear supernatant is the test solution. Similarly prepare a Standard solution of
USP Bromocriptine Mesylate RS in methanol containing 1 mg of bromocriptine per mL and 3 Standard dilutions having final concentrations equivalent to 0.10, 0.30, and 0.50 mg of bromocriptine per mL (equivalent to 1.0, 3.0, and 5.0%, respectively). Separately apply, as 1.5-cm bands, 10-µL portions of the Standard solution and of the 3 Standard dilutions, and 50 µL of the test solution, to a suitable thin-layer chromatographic plate (see
Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel mixture. Dry the plate for 5 minutes in a current of cold air. Develop in a tank lined with filter paper, previously equilibrated for 20 minutes, using a solvent system consisting of a mixture of methylene chloride, dioxane, alcohol, and ammonium hydroxide (180:15:5:0.1) until the solvent front has moved a distance of 10 cm on the plate. Dry the plate under vacuum at room temperature for 15 minutes. Spray evenly with a 0.2% solution of
o-phthalaldehyde in sulfuric acid, and view the plate under long-wavelength UV light. Any spot, other than the principal spot, obtained from the test solution is not greater in size and intensity than the spot obtained from the 3.0% Standard solution; and any remaining spots are not greater in size and intensity than the spot obtained from the 1.0% Standard solution. The sum of the related compounds is not greater than 5.0%.
Assay—
Mobile phase—
Mix 650 mL of acetonitrile with 350 mL of 0.01 M ammonium carbonate.
Standard preparation—
Transfer about 11 mg of
USP Bromocriptine Mesylate RS, accurately weighed, to a 50-mL volumetric flask, dissolve in and dilute with methanol to volume, and mix.
Assay preparation—
Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 10 mg of bromocriptine, to an appropriate container, add 40 mL of methanol, and stir for 20 minutes, protected from light. Quantitatively filter through a fine glass filtering funnel into a 50-mL volumetric flask. Rinse the filter with methanol, adding the rinsing to the filtrate, dilute with methanol to volume, and mix.
Procedure—
Separately inject equal volumes (about 50 µL) of the
Standard preparation and the
Assay preparation into a high-performance liquid chromatograph equipped with a 250- × 4-mm stainless steel column containing packing L1, an UV detector capable of monitoring absorption at 300 nm, and suitable recorder and integrator. The column is maintained at ambient temperature, and the flow rate is adjusted to approximately 2 mL per minute. The coefficient of variation for 3 replicate injections of the
Standard preparation is not more than 3.0%. Calculate the quantity, in mg, of bromocriptine (C
32H
40BrN
5O
5) in the portion of Tablets taken by the formula:
(654.59 / 750.70)50C(AU / AS),
in which 654.59 and 750.70 are the molecular weights of bromocriptine and bromocriptine mesylate, respectively;
C is the concentration, in mg per mL, of
USP Bromocriptine Mesylate RS in the
Standard preparation; and
AU and
AS are the peak areas obtained from the
Assay preparation and the
Standard preparation, respectively.
